There is a rare bug that when you unlock the door using Rocksalt's key and open the door there will still be a barrier like the door was never opened in the first place. The only way to fix is reload a previous save.
If you complete the quest then steal the Repellent Stick (hidden upstairs in Moira's shop) it will be irremovable as it still counts as a quest item but will not weigh anything. You can use it as a weapon but it cannot be dropped and will not appear in your inventory when checking in a container or a shop.
After entering the Tepid Sewers an Enclave deathclaw will immediately spawn in front of you, then die in a matter of seconds. This is possibly somehow connected with the deathclaw control scrambler which basically turns Enclave deathclaws into short-term followers.
Once you go into the sewer it's possible you won't be able to get back out due to a door lock glitch.